When it comes to presidential politics, I sometimes wonder if Republicans are just too divided to do what they need to do in order to win elections -- as in the case of immigration reform. But sometimes I wonder if they really want to win -- or if their candidates would rather be heroes to the party's most extreme elements.

When Republicans use Bill Clinton's sex scandal to raise doubts about the wisdom of electing Hillary Clinton president, they are displaying the tone-deafness that helped lose them the last two presidential elections. Rand Paul accused the former president of "predatory" behavior in having sexual relations with Monica Lewinsky.

Maybe Clinton did behave in a disgraceful manner. But the fact is, the country went through months of acrimonious debate about his conduct and decided he should stay in office.

During that time, Clinton's approval ratings actually rose, while those of congressional Republicans fell sharply. And the First Lady won widespread sympathy and admiration for her determination to preserve her marriage.

So if Paul wants to talk about Monica Lewinsky, Democrats stand to gain. This sort of attack is bound to backfire, for three obvious reasons.

First is that it unfairly impugns Hillary Clinton for her husband's flaws. Second is that it suggests a moralistic GOP preoccupation with matters sexual. Third is that it will strike most younger voters, who have dim or no memories of the scandal, as thunderously irrelevant to the issues of 2016.

It's a losing gambit. But that doesn't mean we've heard the last of it from Paul or his fellow Republicans.